How to define OU specific templates in bill presentment architecture

Hi,

Our client has presence in almost all the major countries.

We have OU wise invoice custom template and associated to a custom program to print the AR invoices.

As and when required, region wise concurrent programs are being run to print the invoice.

The proposal is to globalize the process. instead of multiple print programs, planning to have a solution which will have flexibility in defining the templates based on OU wise print requirements.

I have come across bill presentment architecture where we can define flexible templates.

But I have a query that How can we define multiple templates, one for each OU and how to assign those templates to invoice class. (OU's has to keep specific info on invoice as per the legal or local requirements)